Stipple matrix-plate.



UNITED STATES PATENT OFFICE.

BI'RGER SMITH, OF ST. PAUL, MINNESOTA.

STIPPLE MATRIX-PLATE.

SPECIFICATION forming part of Letters Patent No. 694,1 15, dated February 25, 1902.

Application filed November 2. 1900. Serial No. 35,246. (No model.) 7

To all whom it may concern:

Be it known that I, BIRGER SMITH, a citizen of the United States, residing at St. Paul, in the county of Ramsey, and in the State of Minnesota, have invented certain new and useful Improvements in Stipple Matrix- Plates, of which the following is a specification.

This invention relates to plates upon which engravings are to be transcribed; and it cousists in a base, preferably of metal, and upon Whose surface a thin coating of earthy material is secured, the earthy covering being provided with innumerable indentations at close intervals arranged in rows or forming regular figures on the surface of the plate, thus prod ucing a stipple surface. The earthy covering will generally be about one-fortieth of an inch in thickness and will be secured to the base-plate in any suitable manner, preferably by glue, and the indentations will be from-about one-thirtieth to one-sixtieth of an inch apart and may be arranged in rows either at right angles or diagonally or in any other desired manner. With a plate thus formed the artist is provided with a surface upon which a picture can be readily engraved by cutting through the earthy stipple coating down to the metal case, using his steel point in the same manner as a pen in drawing the picture. When a metal cast is taken from the plate thus engraved, the

. molten metal not only flows into the cut-out a: 00 of Fig. 1.

A represents the metal base, and A the earthy coating, which is necessarily greatly exaggerated as to thickness.

A represents the indentations, which are also greatly exaggerated to illustrate their arrangement more fully.

The result from printing from a plate thus formed is a line-picture on a ground resembling half-tone.

great ease and freedom and rapidity. There is little difficulty in making the cast, because of the shallownessof the earthy mold. No

routing will be required between theliues of the engraving, thus saving much valuable time and work by the stereotyper. The print from a plate thus formed presents an attractive picture and from extended practical experience has proved to be far superior to the common chalk plate.

The earthy coating on the plate will be formed with a surface of sufficient hardness to protect the stipple from being destroyed by handling if not rubbed too hard. At the same time the surface must not be so hard as to hamper the engraving in any Way. The coating must adhere to the metal base in such a manner that it will not chip 0% between the lines or crumble under the engrav'ingtools, so that the artist can make the finest as well as coarsest lines on the plate Without difficulty. The indentations forming the stipple surface thus become a part of the plate and serve an important coactive function with the earthy engraving covering or coating upon the metal subbase or foundation and enable the artist to produce an effect which cannot be produced by the smooth-surfaced plate not having the stipple indentations.

I am aware that paper having projections formed thereon have been heretofore employed, the projections forming a stipple-like surface and forming What is known as fstippled lithographic paper. This paper is formed by pressing smooth paper upon a matrix of lithographic stone having the stipple indentations therein, whereby the material of the paper is impressed into the indentations in the matrix, thereby producing upon the paper projections corresponding to the indentations in the matrix. This matrix is capable of employment only to produce the stipple-paper and cannot be employed for the same purpose as in my invention, neithercan it be employed in an analogous sense, as its only use is to produce the projecting stippled surface upon paper upon which drawings with a coating of earthy substance capable of being engraved, and with minute indentations in said earthy coating to form astipple ground, substantially as set forth.

In testimony whereof I allix my signature [5 in presence of two witnesses.

BIRGER SMITH. Witnesses:

L. FEESER, J11, ANNA MURPHY. 

